This review was first published in The Pittsburgh Post-Gazette Dec. 3, 2023.

A post-midnight doorbell jolts Katie out of sleep at her new home and job as the caretaker of a nature preserve. She looks out to see an injured woman with blood dripping down the side of her face. Does she open the door?

Would you?

Pittsburgh author Jessica Strawser begins “The Last Caretaker” like an action-movie thriller, as she drops the reader into the story. Quickened heart rates continue to surge and ebb throughout this suspenseful book.

Ms. Strawser, author of Book of the Month bestseller “Not That I Could Tell,” gives readers a master class in distrust through the eyes of Katie, a recent divorcée who wants and needs to leave her old life behind and start again. After her divorce left her ​​discomfited and deflated, she is given that chance through one of her oldest friends, Bess, when Bess asks Katie to be the resident caretaker of Grove Farm nature preserve.

After masterful suspense sequences by Ms. Strawser, Katie discovers that she has unknowingly entered into a powerful underground network of women who help women in abusive relationships.

Katie agonizes about whether to push ahead, but when she realizes the system will break down without her, she forges on, one step at a time, a metaphorical middle-finger to her emotionally abusive ex-husband.

Philosophers have given us tools such as Aristotle’s Golden Mean and John Rawls’ Veil of Ignorance to help societies make ethical decisions. But no male philosopher could anticipate this, or help Katie figure out what to do next. She’s in a fly-by-the-seat-of-her-pants situation alone.

Sworn to secrecy about her new, more perilous caretaking responsibilities, Katie eyes her new surroundings, and her life, with renewed mistrust. Did her friend Bess know about the network of women called the Sequence? Do visitors to the preserve suspect she is hiding women on the property? Why did the previous caretaker quit suddenly?

Is her safety in question? That question embodies the tenor of the book.

Yet the dark undercurrent of the novel is punctured by many moments of lighthearted, carefree humor in part because, even though she’s agreed to work in nature, she and nature have never spent much time together. Her sister’s children also provide laughs when they come to visit the preserve.

But the amusement is short-lived. As the book careens toward its end, the readers will feel a sense of dread on Katie’s behalf and might slip into a moral and ethical quagmire the deeper they go.

Readers will ponder along with Katie, as things that were once benign begin to take on new meaning, such as the stitched Mark Twain quote hanging in the caretaker’s home she took over: “It is never wrong to do the right thing.” Readers will watch Katie struggle with how to do the right thing, but also what that might be.

Part of the human experience is learning moral and ethical boundaries, yet some situations are dicey, and what is right is less certain. To risk the courage to move forward and through situations — even and especially in the unknown — is a learned skill. Ms. Strawser navigates these waters with nimbleness, and readers might finish the book with a new sense of right from wrong — or, at the least, question their own beliefs, which is the power of a good book.

Meredith Cummings is a freelance journalist and teaching assistant professor of journalism at Lehigh University.